As one example of a connector assembly, there is known a connector assembly comprising a receptacle connector adapted to be mounted on a circuit board and a plug connector adapted to be fittingly connected to the receptacle connector and to be mounted on another circuit board (Patent Document 1).
Referring to FIGS. 8A and 8B, a connector assembly disclosed in Patent Document 1 will be described. FIG. 8A is a perspective view showing the connector assembly comprising a plug connector 1 and a receptacle connector 2 in a state before they are fitted together. FIG. 8B is a perspective view showing the plug connector 1, shown in FIG. 8A, with its top and bottom reversed.
In FIG. 8A, the plug connector 1 and the receptacle connector 2 are circuit board connectors adapted to be respectively mounted on mounting surfaces of different circuit boards (not illustrated) and are adapted to be fitted to each other in a fitting direction which is a direction perpendicular to the mounting surfaces of the circuit boards (vertical direction in FIG. 8A).
The plug connector 1 comprises a plug housing 10 having a generally rectangular parallelepiped external shape and a plurality of plug terminals 20 held by the plug housing 10. The plurality of plug terminals 20 are held by the plug housing 10 with integral molding such that contact portions of the plug terminals 20 are arranged in one direction parallel to the mounting surface of the circuit board (not illustrated). The plurality of plug terminals 20 include a pair of signal terminals 30 held by the plug housing 10 at its middle position in the arrangement direction of the above-mentioned contact portions and a pair of power supply terminals 40 having a shape different from that of the signal terminal 30 and held by the plug housing 10 on its end sides in the arrangement direction of the above-mentioned contact portions.
The plug housing 10 is formed of an electrically insulating material such as a resin and extends in a longitudinal direction parallel to the arrangement direction of the contact portions of the plug terminals 20. The plug housing 10 has a bottom wall 11 parallel to the mounting surface of the circuit board and, as shown in FIG. 8B, a frame-like outer peripheral wall 12 extending upward (downward in FIG. 8A) from the outer peripheral portion of the bottom wall 11. The outer peripheral wall 12 is formed as a fitting portion which is fitted into a later-described receiving space 56 of the receptacle connector 2 when fitting the connectors together. The outer peripheral wall 12 has a pair of side walls 13 extending in the above-mentioned arrangement direction and a pair of end walls 14 extending in a connector width direction perpendicular to the above-mentioned arrangement direction and each connecting end portions of the pair of side walls 13 to each other.
As shown in FIG. 8B, on an outer surface of each of the pair of side walls 13, a to-be-guided groove portion 13A extending vertically is formed at a position between the signal terminal 30 and one of the pair of power supply terminals 40 in the above-mentioned arrangement direction. In the process of fitting the connectors together, the to-be-guided groove portions 13A respectively receive later-described guide elongated protrusions 54A of the receptacle connector 2 so as to be guided in the above-mentioned arrangement direction and the connector width direction by the guide elongated protrusions 54A. Further, on an outer surface of each of the pair of end walls 14, a recess 14A is formed at an intermediate position in the connector width direction. In the recess 14A, a later-described plug end plate portion 44 of the power supply terminal 40 is located. In a space forming the recess 14A, a space 14A-1 located between the end wall 14 and the plug end plate portion 44 in the above-mentioned arrangement direction is formed as a space for allowing elastic displacement of the plug end plate portion 44 in its plate thickness direction in the process of fitting the connectors together as will be described later.
In FIG. 8B, a space surrounded by the outer peripheral wall 12 and opening upward is formed as a receiving space 15 for receiving an insular projecting wall portion 52 formed in the receptacle connector 2. Further, the plug housing 10 has a to-be-guided wall portion 16 rising upward from the bottom wall 11 in the receiving space 15 at a position adjacent to the end wall 14, provided with the one of the power supply terminals 40 (the one on the left side in FIG. 8B), in the above-mentioned arrangement direction at a middle position in the connector width direction. The to-be-guided wall portion 16 has a wall thickness direction in the connector width direction and is joined to the one of the end walls 14. When fitting the connectors together, the to-be-guided wall portion 16 enters a guide groove portion 52B of the receptacle connector 2 from above so as to be guided in the above-mentioned arrangement direction and the connector width direction by the guide groove portion 52B.
As shown in FIG. 8A, the signal terminals 30 are held by the respective side walls 13 of the plug housing 10 with integral molding at its middle position in the above-mentioned arrangement direction. Each signal terminal 30 is formed by bending a belt-like piece, obtained by punching a metal plate, in its plate thickness direction. The signal terminal 30 has a straight connecting portion 31 (FIG. 8B) extending outward in the connector width direction from the side wall 13 at substantially the same height position as the bottom wall 11 of the plug housing 10 and a U-shaped portion which is bent downward continuously from the connecting portion 31 and folded back in a U-shape so as to be held by the side wall 13. This U-shaped portion extends along the side wall 13 and is exposed such that its U-shaped plate surface forms the same level surface as the side wall 13.
The connecting portion 31 is adapted to be connected by soldering to a corresponding signal circuit portion of the circuit board (not illustrated). Further, of two leg portions of the U-shaped portion of the signal terminal 30, one located on the inner surface side of the side wall 13 (the receiving space 15 side on the plug connector side) is formed as a contact portion 32 for contact with a later-described receptacle signal terminal 70 of the receptacle connector 2. The contact portion 32 is a flat plate surface exposed on the inner surface side of the side wall 13 and is adapted to be brought into contact with a corresponding contact portion 71A of the receptacle signal terminal 70. The other leg portion located on the outer surface side of the side wall 13 is formed as a locking portion 33 for engagement with a to-be-locked projection 74A of an inner leg portion 74 of the receptacle signal terminal 70. The locking portion 33 has a locking recess 33A which is adapted to receive the to-be-locked projection 74A and formed by, for example, pressing so as to be recessed from the plate surface.
As shown in FIG. 8A, the receptacle connector 2 comprises a receptacle housing 50 having a generally rectangular parallelepiped external shape and a plurality of receptacle terminals 60 held by the receptacle housing 50. The plurality of receptacle terminals 60 are held by the receptacle housing 50 with integral molding such that corresponding contact portions of the receptacle terminals 60 are arranged in one direction parallel to the mounting surface of the circuit board (not illustrated). The plurality of receptacle terminals 60 include the pair of receptacle signal terminals 70 held by the receptacle housing 50 at its middle position in the arrangement direction of the above-mentioned corresponding contact portions. The plurality of receptacle terminals 60 further include a pair of end-side receptacle terminals 80 as power supply terminals (hereinafter referred to as receptacle power supply terminals 80) having a shape different from that of the receptacle signal terminal 70 and held by the receptacle housing 50 on its end sides in the arrangement direction of the above-mentioned corresponding contact portions.
The receptacle housing 50 is formed of an electrically insulating material such as a resin and has a longitudinal direction in the arrangement direction of the corresponding contact portions of the receptacle terminals 60. The receptacle housing 50 has a bottom wall (illustration omitted) parallel to the mounting surface of the circuit board, the projecting wall portion 52 rising upward from a middle portion of this bottom wall and extending in the above-mentioned arrangement direction, and a frame-like outer peripheral wall 53 rising upward from the bottom wall and surrounding the projecting wall portion 52. The outer peripheral wall 53 has a pair of side walls 54 extending in the above-mentioned arrangement direction and a pair of end walls 55 extending in a connector width direction perpendicular to the above-mentioned arrangement direction and each connecting end portions of the pair of side walls 54 to each other. A rectangular groove-like space opening upward between the projecting wall portion 52 and the outer peripheral wall 53 is formed as the receiving space 56 for receiving the outer peripheral wall 12 which serves as the fitting portion of the plug connector 1.
As shown in FIG. 8A, the projecting wall portion 52 provided like an island on the bottom wall of the receptacle housing 50 is formed with groove portions 52A on its both side surfaces (surfaces perpendicular to the connector width direction) at the middle position in the above-mentioned arrangement direction. The groove portions 52A each provide a space for allowing elastic displacement of an elastic arm portion of the receptacle signal terminal 70 and are formed so as to be recessed from the above-mentioned both side surfaces and to extend vertically.
Each power supply terminal 40 is formed by bending a metal plate as a single member and, as shown in FIG. 8A, is held by the side walls 13 and the end wall 14 with integral molding at an end side portion, in the above-mentioned arrangement direction, of the outer peripheral wall 12 of the plug housing 10. As shown in FIG. 8B, each power supply terminal 40 has a base portion 41 extending along an upper surface (lower surface in FIG. 8A) of the end side portion of the plug housing 10 and plug side plate portions 42 bent from the base portion 41 and respectively extending along the outer surfaces of both side walls 13 of the plug housing 10. The power supply terminal 40 further has connecting portions 43 each bent at a lower end of the plug side plate portion 42 and each extending outward in the connector width direction and the plug end plate portion 44 bent from the base portion 41 and extending along an outer end surface of the end wall 14 of the plug housing 10.
As shown in FIG. 8B, the base portion 41 of the power supply terminal 40 is exposed such that a flat upper surface of the base portion 41 forms the same level surface as upper surfaces of the side walls 13 and the end wall 14 in a region except the corners of the end side portion of the plug housing 10. On the other hand, the plug side plate portion 42 is exposed such that a flat plate surface of the plug side plate portion 42 forms the same level surface as the outer surface of the side wall 13. The plug side plate portion 42 serves as a contact portion for contact with a corresponding contact portion 81A of the receptacle power supply terminal 80 provided in the receptacle connector 2.
Next, the connecting portion 43 of the power supply terminal 40 is located at substantially the same height as the bottom wall 11 (FIG. 8A) of the plug housing 10 and is adapted to be connected by soldering to a corresponding power supply circuit portion of the circuit board (not illustrated). As shown in FIG. 8B, a bent portion where the plug side plate portion 42 and the connecting portion 43 are joined together is covered with a part of the plug housing 10. Further, the plug end plate portion 44 of the power supply terminal 40 is such that its both side edge portions extending vertically are held by the plug housing 10 with integral molding in the recess 14A of the end wall 14 of the plug housing 10. A plate surface of the plug end plate portion 44 has a locking stepped portion 44A which is formed by, for example, pressing and protrudes outward in the above-mentioned arrangement direction to form a step. The locking stepped portion 44A is engageable with a to-be-locked stepped portion 82B-1 of a to-be-locked plate portion 82B of the receptacle power supply terminal 80 in a connector extraction direction.
As described above, in the connector assembly of Patent Document 1, the receptacle housing 50 of the receptacle connector 2 is formed of the resin material and has the shape in which the projecting wall portion 52 rising from the bottom wall facing the circuit board and extending in the terminal arrangement direction is surrounded by the outer peripheral wall 53 rising from the bottom wall. The rectangular groove-like space opening upward between the projecting wall portion 52 and the outer peripheral wall 53 is formed as the receiving space 56 for receiving the fitting portion of the plug connector 1. On the other hand, the plug housing 10 of the plug connector 1 is formed of the resin material and has, as the fitting portion, the outer peripheral wall 12 rising from the bottom wall 11 facing the other circuit board and having the shape conforming to the receiving space 56 of the receptacle connector 2. The outer peripheral wall 12 of the plug connector 1 has the two side walls 13 extending in the terminal arrangement direction and the two end walls 14 extending in the connector width direction perpendicular to the terminal arrangement direction and each connecting the end portions of the two side walls to each other. The groove-like space surrounded by the outer peripheral wall 12 is formed at the fitting portion of the plug connector 1.
When fitting the receptacle connector 2 and the plug connector 1 to each other, the fitting portion of the plug connector 1 is fitted into the receiving space 56 of the receptacle connector 2 from above, while the projecting wall portion 52 of the receptacle connector 2 enters the groove-like space surrounded by the fitting portion (outer peripheral wall 12) of the plug connector 1 from below.
In the meantime, as will be described in detail later, usually, guide portions are formed at both ends in a longitudinal direction of a plug connector, while to-be-guided portions for receiving the guide portions are formed at both ends in a longitudinal direction of a receptacle connector. The to-be-guided portion of the receptacle connector is called a fitting frontage portion and has a recess formed by a peripheral wall having a generally U-shape in plan view. The to-be-guided portions of the receptacle connector and the guide portions of the plug connector are each provided with a metal member for achieving a function of connecting to a power supply and a function (locking engagement) of locking the fitting of the plug connector into the receptacle connector, particularly the fitting of the guide portion into the to-be-guided portion. In terms of the connector assembly shown in FIGS. 8A and 8B, the function of locking the fitting is achieved by the locking stepped portions 44A on the plug connector 1 side and the to-be-locked stepped portions 82B-1 on the receptacle connector 2 side.